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Instrument: LRR : Laser Retro-Reflector
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Associated Platforms
TSX
GOCE
ERS-2
ERS-1
ENVISAT
CRYOSAT-2

Related Data Sets
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Description
The European Remote Sensing Satellites (ERS-1 and ERS-2) are equipped
with a Laser Retroreflector (LRR), a passive optical instrument
operating in the infra-red, to permit ranging of the satellite by the
use of Laser Tracking Stations, and therefore the accurate
determination of its height. These measurements allow:

- calibration of the Radar Altimeter altitude measurements with an
error of 10 cm
- improvement of the satellite orbit determination ensuring the
production of a global ephemeris accurate to better than 1-2 m for the
radial component.

The operating principle is to measure the time of a round trip of
laser pulses reflected from an array of corner cubes mounted on the
Earth-facing side of the spacecraft's Payload Electronics Module. This
array consists of a hemispherical housing with an arrangement of one
nadir-looking corner cube in the centre, surrounded by an angled ring
of eight corner cubes. Each corner cube is individually made to
compensate for satellite motion in reflecting incident laser energy
back exactly along its incoming path. This allows laser ranging for
satellite passes in the range of 0-360 degrees azimuth and 30 to 90
degrees elevation at the ground.

Instrument characteristics:

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Wavelength: 350-800 nm optimised for 532 nm
Efficiency: less or equal than 0.15 end-of-life
Reflection Coefficient: less or equal than 0.80 end-of-life
Field of view: elev. half-cone angle 60 degrees; azimuth 360 degrees
Diameter: more or equal than 20 cm
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For any query, please refer to:

ESA/ESRIN Earth Observation Help Desk

http://earth.esa.int

E-mail: eohelp@esa.int

Phone: +39 06 94180777

Fax: +39 06 94180292

Address:

ESA/ESRIN

Via G.Galilei

00044 Frascati

Italy

Online Resources
http://envisat.esa.int/instruments/lrr/

Instrument Logistics
Instrument Owner: ESA